High-absorbance resonant-cavity-enhanced free-standing Ge photodetector for infrared detection at 1550 nm wavelength
High-absorbance resonant-cavity-enhanced free-standing Ge photodetector for infrared detection at 1550 nm wavelength
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DOI：
10.1063/5.0152110
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发表时间：
2023-07
期刊：
影响因子：
1.6
通讯作者：
Ching-Yu Hsu;Z. Pei;Jia-Ming Liu
中科院分区：
文献类型：
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作者：
Ching-Yu Hsu;Z. Pei;Jia-Ming Liu
设计了一种基于硅基片的底部分布布拉格反射器（DBR）自支撑谐振腔增强（RCE）锗薄膜吸收体，用于1550 nm波长的红外探测。独立结构在优化DBR的周期数、层布置和每层厚度方面提供了高度的自由度。一个SiO2/Si DBR，这是兼容的Si处理工艺被用于底部的Ge薄膜构成的RCE结构。根据我们的理论研究，SiO2低折射率层必须放置在Ge层旁边，以利用SiO2和Ge之间的折射率的大差异来实现DBR的高反射率。在这种设计中，该结构可以达到85.90%的吸收率与DBR的三个周期的底部和抗反射氧化层上的Ge层的顶面。在没有抗反射氧化层的情况下，吸收率增加到99.17%。该设计为硅基光子系统中高响应度锗红外探测器的研制铺平了道路。
A novel free-standing resonant-cavity-enhanced (RCE) Ge thin-film absorber is designed with a bottom distributed Bragg reflector (DBR) for infrared photodetection at 1550 nm wavelength based on a Si substrate. The free-standing structure offers a high degree of freedom in optimizing the number of periods, the layer arrangement, and the thickness of each layer of the DBR. A SiO2/Si DBR that is compatible with Si processing technology is used on the bottom of the Ge thin film to construct the RCE structure. Based on our theoretical study, the SiO2 low-index layer must be placed next to the Ge layer to utilize the large difference in the refractive indices between SiO2 and Ge to achieve high reflectance for the DBR. In this design, the structure can reach an absorbance of 85.90% with a DBR of three periods on the bottom and an antireflective oxide layer on the top surface of the Ge layer. Without the antireflective oxide layer, the absorbance is increased to 99.17%. The design paves the way for high-responsivity Ge infrared photodetectors in Si-based photonic systems.